Involvement of the coeliac ganglion in the luteotrophic effect of androstenedione in late pregnant rats

Using the ex vivo coeliac ganglion-superior ovarian nerve-ovary system at the end of pregnancy when luteal regression starts, we investigated whether, when administered systemically or when added directly to the ganglion compartment, androstenedione (A(2)) can reverse such regression, and whether the neural (noradrenaline (NA)) and endocrine (A(2)) joint action modifies the release of ovarian progesterone. The experimental groups were as follows: group 1 - A(2) injected systemically 48 h before incubation of the system (A(2))(s); group 2 - A(2) directly added to the ganglion compartment (A2)g; group 3 - A(2) injected 48 h before incubation of the system with NA in the ganglion compartment (A(2) + NA); group 4 - A(2) plus NA added to the ganglion compartment (NA + A(2))(g). The controls were ex vivo systems without treatment (control), and with the addition of NA alone in the ganglion compartment (NA). The results were as follows. For (A(2))(s) versus control, progesterone increased on days 19 and 21 of pregnancy at all the studied times and only at 180 min on day 20. For (A(2) + NA) versus (A(2))(s), progesterone increased on days 19 and 21. For (A(2) + NA) versus NA, progesterone increased at all the studied times on days 19 and 21 and at 180 min on day 20. For (A(2))(g) versus control, progesterone significantly increased every pregnancy day. For (NA + A(2))(g) versus (A(2))(g), progesterone decreased at 120 and 180 min on day 19. For (NA + A(2)). versus NA, progesterone increased on days 20 and 21. We can conclude that A(2) can reverse the functional regression of the corpus luteum either systemically or, what is more surprising, when directly added to the coeliac ganglion, whose action on the ovary is exerted via superior ovarian nerve.